Gaseous electric discharge device



GASEOUS ELECTRIC DISCHARGE DEVICE Filed Aug. 12, 1932 5V 5 I 5 i) INVENTOR .5 6 I 6 ATTORNEY Patented Mar. 13, 1934 1,951,155 GASEOUS ELECTRIC DISCHARGE DEVICE Hendrik Lems, Eindhoven, Netherlands, assignor to General Electric Company, a corporation of New York Application 4 Claims.

The present invention relates to gaseous electric discharge devices generally and moreparticularly the invention relates to means to start and operate such devices.

It is now known in the art that the starting of electric discharge devices having cold main discharge supporting electrodes is facilitated by providing elongated auxiliary electrodes in the elongated container of the device. One of said electrodes extends from each of said main electrodes to the center of said container and is connected to a main electrode through a resistance. Heretofore such auxiliary electrodes have had a tortuous shape so that their electrical resistance per unit of length is greater than that of the gas column between said electrodes' When a suitable potential is applied to such devices an electric discharge is struck between the adjacent ends of said. auxiliary electrodes. Due to the high resistance of the auxiliary electrodes said discharge travels from the adjacent ends thereof toward the main discharge supporting electrodes and thus the main discharge is started in the device.

The object of the present invention is to provide a gaseous electric discharge device of the above type which is of a simpler structure than those now known in the art and which is therefore manufactured much more cheaply. A further object of the invention is to avoid sputtering of the material of the auxiliary electrodes, characteristic of prior devices of this type. Still further objects and advantages attaching to the device and to its use and operation will be apparent to those skilled in the art from the following particular description and from the appended claims.

In accordance with these objects the auxiliary electrodes are straight wires and are of such material and. dimensions that their resistance per unit of length is less than that of the gas column between the main discharge supporting electrodes. Applicant has discovered that auxiliary electrodes having such electrical characteristics are as effective in facilitating the starting of the device as the tortuous shaped auxiliary electrodes used heretofore and that the use of straight wires simplifies the manufacture of such devices.

Applicant avoids the sputtering of particles of electrode material from the auxiliary electrodes by covering said electrodes with insulation material at those parts thereof where sputtering takes place, namely, the adjacent ends of said auxiliary electrodes and the parts of said auxiliary elec- August 12, 1932, Serial No. 628,577 Germany August 19, 1931 trodes adjacent the main discharge supporting electrodes. Where desired, a grid is interposed between the wall of the container and the parts of said auxiliary electrode where sputtering takes place, said grid catches the sputtered particles W to prevent the deposition of said particles on the wall of the container of the device.

In the drawing accompanying and forming part of this specification two embodiments of the invention are shown in which,

Fig. l is a schematic view of one embadiinent of the invention and Fig. 2 is a similar view of another embodiment of the invention.

Like numbers denote like parts in both figures. 7

Referring to Figure 1 of the drawing the electric discharge device comprises an elongated container 1 having an electrode chamber 2 and an electrode 3 sealed into stem 4 at each end thereof. Each of said electrodes 3 has inleads 5 and 6, is capable of electron emission when heated and consists of a coiled wire coated with barium oxide. Any other suitable type of thermionic electrode, such as a Pirani electrode or a Hull electrode, well known in the art, is used when desired. Said container 1 is filled with a discharge supporting gaseous atmosphere consisting of a rare gas, a common gas, a vapor, or a mixture of these gases, such as argon and mercury. An auxiliary electrode '7 is sealed into each of said stems 4 and extends toward the opposite end of said container 1. The adjacent ends of said auxiliary electrodes '7 are physically connected by a body 10 of insulation material, such as porcelain, the end of one of said electrodes 7 is wound around the outside of said body 10 and the end of the other of said electrodes 7 is imbedded or attached to the interior of said body 10. Each of said electrodes 7 is connected to one of the current inleads 6 through resistance 9 by lead 8.

The value of resistances 9 depends on various factors such as gas pressure, length of container 1 and so forth. Generally, however, the value of said resistances 9 is between 100 and 10,000 100 ohms. Where desired a capacitance or choke coil is used in place of each of said resistances 9.

When a current of 110, 220 or 380 volts is applied across the terminals ofthe electric discharge device described above an electric dis- 1% charge takes place between the adjacent end parts of said auxiliary electrodes '7. The ionization of the gas in the center of container 1 by said discharge facilitates the starting of the main discharge between said electrodes 3. The parts of 110 said auxiliary electrodes 7 adjacent the thermionic electrodes 3 has a positive charge when said electrodes 3 act as the cathode and as a result the electrons emitted by said electrodes 3 are attracted to the positively charged parts of said auxiliary electrodes '7 which diminishes the space charges in the region of said main electrodes 3 to facilitate further the starting of the positive column discharge in said device. When the device is operating on alternating current the above described phenomena talzes place on each half-cycle of the alternating current.

The embodiment of the invention shown in Fig. 2 is in all respects the same as that shown in Fig. 1 except that the parts of said auxiliary electrode 7 adjacent the main electrodes 3 are surrounded by insulation tubes 11 of lavite, or nonsputtering oxides, for example, to prevent sputtering of material from those parts of said auxiliary electrodes 7 as I have" found by experiment that a heavy sputtering of material takes place at said parts. The adjacent ends of said auxiliary electrodes '1 are physically connected by a glas head 12 and a wire mesh grid or screen is interposed between said end parts of said electrodes i and the inner walls of said container 1 and surrounds the adjacent end parts of said auxiliary electrodes '7 to catch the sputtered particles or material from said electrodes 7 and thus prevents the deposition of said particles on the wall of said container 1. Said grid i3 is supported by spring rings 14 pressing against the inner wall of said container 1.

While I have shown and described and have pointed out in the annexed claims certain novel features of the invention, it will be understood that various omissions, substitutions and changes in the forms and details of the device illustrated and in its use and operation may be made by those skilled in the art without departing from the broad spirit and scope of the invention, for example, several pairs of auxiliary electrodes may be used, the auxiliary electrodes may be in different parts of the container, and/or may overlap for part of their length, in which case the overlapping part of each electrode should not exceed 1/3 its total length, and the auxiliary electrodes may be connected to either of said main electrodes as desired.

What I claim as new and desire to secure by Letters Patent of the United States is:-

1. An electric discharge device comprising a container, a gaseous atmosphere therein, electrodes sealed therein, at least two of said electrodes being main discharge supporting electrodes, another of said electrodes extending from one or" said main electrodes to the other, the electrical resistance of said last named electrode being less per unit of length than that of the ionized gas column between said electrodes.

2. An electric discharge device comprising a container, a gaseous atmosphere, electrodes sealed therein, at least two of said electrodes being main discharge supporting electrodes, another of said electrodes extending from one of said main electrodes to the other, the electrical resistance of said last named electrode being less per unit of length than that of the ionized gas column between said electrodes, said last named electrodes being connected through an impedance to one of said main electrodes.

3. An electric discharge device comprising a container, a gaseous atmosphere therein, electrodes sealed therein, at least two of said electrodes being main discharge supporting electrodes, two other electrodes being elongated electrodes extending from opposite ends of said container toward the center thereof and separate from the walls oi said container, the adjacent ends of elongated electrodes being physically joined by a body of insulation material, part of elongated electrodes being adjacent one of said main discharge supporting electrodes, each of said elongated electrodes being connected through an impedance to one of said main discharge supporting electrodes, the electrical re- .--istance of said elongated electrodes being less per init of length than the gas column between said nain discharge supporting electrodes.

4. An electric discharge device comprising a container, a gaseous atmosphere therein, electrodes sealed therein, at least two of said electrodes being main discharge supporting electrodes, two other electrodes being elongated electrodes extending from opposite ends of said container toward the center thereof and separate from the walls of said container, the adjacent ends of said elongated electrodes being physically joined by a body of insulation material, the part of each said elongated electrode adjacent one of said main electrodes being covered with insulation material.

HENDRIK LEMS.

CJI 

